Temperature Dependence of Electron Leakage Current in InGaN Blue Light-Emitting Diode Structures.

We investigated the temperature dependence of the electron leakage current in the AlGaN electron-blocking layer (EBL) of an InGaN/GaN blue light-emitting diode (LED) structure at temperatures between 20 and 100 °C. The percentage of electron leakage current was experimentally determined by fitting the measured external quantum efficiency of an LED using the ABC recombination model. The electron leakage current decreased significantly as the temperature increased from 20 to 100 °C. The experiment obtained temperature-dependent electron leakage current was also found to agree well with the simulation results. This counter-intuitive temperature dependence of the electron leakage current resulted from an increase in potential barrier for electrons with increasing temperature due to the increased ionized acceptor concentration in the EBL with temperature. Moreover, the results obtained for the temperature-dependent electron leakage were consistent with the thermionic emission model. The results of the temperature dependence reported here are expected to provide insight into the thermal droop of GaN-based LEDs.